Screening cosmetic composition comprising one nanopigment of metallic oxide and one fat-soluble screening polymer

ABSTRACT

The present invention is directed to a composition for screening out ultraviolet radiation, comprising, in association, at least one nanopigment of metallic oxide and at least one UV-screening fat-soluble polymer.

This is a divisional application of application Ser. No. 08/039,324,filed Apr. 23, 1993, now U.S. Pat. No. 5,733,895 which is a 371 ofPCT/FR92/00821, filed Aug. 25, 1992.

The subject of the present invention is a composition for screening outultraviolet radiation, comprising, in association, at least onenanopigment of metallic oxide and at least one UV-screening fat-solublepolymer.

It is known that light radiation with wavelengths of between 280 and 400nm permit the tanning of the human epidermis and that rays withwavelengths of between 280 and 320 nm, known by the name UV-B, alsocause erythemas and skin burns which can hamper the development of thetan.

However, while UV-B rays with wavelengths of between 280 and 320 nm playa preponderant part in the production of solar erythema and must bescreened out, it is nevertheless a fact that UV-A rays with wavelengthsof between 320 and 400 nm which cause tanning of the skin are alsocapable of inducing its degradation especially in the case of asensitive skin or a skin continuously exposed to solar radiation. UV-Arays cause in particular a loss of elasticity of the skin and theappearance of wrinkles which result in early ageing. They promote theonset of the erythemal reaction or amplify this reaction in certainsubjects and may even be responsible for phototoxic or photoallergicreactions.

Compounds are known which have the property of absorbing ultravioletradiation in the erythemal region while allowing the radiationresponsible for tanning to pass through and it has already been proposedto use such compounds as "sunscreen" agents in cosmetic compositionswhich promote the acquisition of skin tan while avoiding skin burns andirritations.

Synthetic or natural carbon-containing polymers and siloxane polymerscarrying an ultraviolet-absorbing group are also known which possess theadvantage of reducing or even suppressing the penetration of thescreening compound into the body.

Metallic oxides such as titanium oxide are useful because of theirultraviolet ray diffusion and reflection properties over a broad band.However, the effectiveness of the cosmetic compositions containing onlymetallic oxides, expressed by the solar protection factor which isgenerally called "protection index" or PI, is inadequate for verysensitive skins or skins continuously exposed to solar radiation,especially with respect to the UV-B protection index.

The protection index or PI may be expressed by the ratio of theirradiation time required to reach the erythematogenic threshold withthe UV-screening agent to the time required to reach the erythematogenicthreshold without a UV-screening agent.

Cosmetic compositions containing only "screening polymers" have the samedisadvantage.

In the following text, a polymer of hydrocarbon or siloxane structure,carrying at least one ultraviolet-absorbing group, will be called"screening polymer".

Moreover, at the industrial level, it is of course advantageous to haveUV-screening agents which make it possible, at low concentrations, toobtain anti-sun compositions with a high protection index.

The Applicant has just discovered that by combining at least onenanopigment of metallic oxide, having a particle size less than 100 nm,with at least one fat-soluble screening polymer, in a cosmeticallyacceptable carrier, there was surprisingly obtained, for a compositioncontaining a given concentration of the nanopigment and the screeningpolymer taken together, a protection index, especially a UV-B protectionindex, substantially greater than the protection indices of compositionscontaining either a nanopigment, or a screening polymer, at the sameconcentration and in the same carrier.

The subject of the present invention is therefore a cosmetic compositionfor screening out ultraviolet radiation with wavelengths of between 280and 400 nm, which contains at least one nanopigment of metallic oxideand at least one screening polymer chosen from fat-soluble polymers witha hydrocarbon structure and polymers with a siloxane structure, in acosmetically acceptable carrier.

The subject of the present invention is also a process for protectingthe human epidermis and the hair against ultraviolet radiation withwavelengths of between 280 and 400 nm, which consists in applying to theskin an effective amount of the abovementioned screening cosmeticcomposition comprising, in association, at least one nanopigment ofmetallic oxide and at least one fat-soluble screening polymer.

The pigments of metallic oxides are chosen from titanium, zinc, cerium,zirconium or iron oxides or mixtures thereof. In the presentapplication, "nanopigments" are understood to mean pigments with a meandiameter of less than 100 nanometers, preferably of between 5 and 50nanometers. These nanopigments may be coated or uncoated.

The coated pigments are pigments which have undergone one or moresurface treatments of a chemical, electronic, mechanicochemical and/ormechanical nature with compounds, as described for example in Cosmetics& Toiletries, February 1990, Vol. 105, p. 53-64, such as amino acids,beeswax, fatty acids, fatty alcohols, anionic surfactants, lecithins,sodium, potassium, zinc, iron or aluminum salts of fatty acids, metallicalkoxides (of titanium or aluminum), polyethylene, silicones, proteins(collagen, elastin), alkanolamines, silicon oxides, metallic oxides orsodium hexametaphosphate.

The coated pigments are more particularly titanium oxides coated:

with silica, such as the product "SUNVEIL" from the company IKEDA,

with silica and iron oxide, such as the product "SUNVEIL F" from thecompany IKEDA,

with silica and alumina, such as the products "MICROTITANIUM DIOXIDE MT500 SA" and "MICROTITANIUM DIOXIDE MT 100 SA" from the company TAYCA,"TIOVEIL" from the company TIOXIDE,

with alumina, such as the products "TIPAQUE TTO-55(B)" and "TIPAQUETTO-55(A)", from the company ISHIHARA, and "UVT 14/4" from the companyKEMIRA,

with alumina and aluminum stearate, such as the product "MICROTITANIUMDIOXIDE MT 100 T" from the company TAYCA,

with alumina and aluminum laurate, such as the product "MICROTITANIUMDIOXIDE MT 100 S" from the company TAYCA,

with iron oxide and iron stearate, such as the product "MICROTITANIUMDIOXIDE MT 100 F" from the company TAYCA,

with zinc oxide and zinc stearate such as the product "BR 351" from thecompany TAYCA,

with silica, alumina and silicone, such as the products "MICROTITANIUMDIOXIDE MT 600 SAS" and "MICROTITANIUM DIOXIDE MT 500 SAS" from thecompany TAYCA,

with silica, alumina, aluminum stearate and silicone, such as theproduct "STT-30-D-S" from the company TITAN KOGYO,

with alumina and silicone, such as the product "TIPAQUE TTO-55(S)" fromthe company ISHIHARA,

with triethanolamine, such as the product "STT-65-S" from the companyTITAN KOGYO,

with stearic acid such as the product "TIPAQUE TTO-55(C)" from thecompany ISHIHARA,

with sodium hexametaphosphate, such as the product "MICROTITANIUMDIOXIDE MT 150 W" from the company TAYCA.

There may also be mentioned the mixtures of metallic oxides, especiallyof titanium dioxide and cerium dioxide, including the equiponderalmixture of titanium dioxide and cerium dioxide, coated with silica,which is sold by the company IKEDA under the name "SUNVEIL A" as well asthe mixture of titanium dioxide and zinc dioxide coated with alumina,silica and silicone, such as the product "M 261" sold by the companyKEMIRA, or coated with alumina, silica and glycerin, such as the product"M 211" sold by the company KEMIRA.

The uncoated titanium oxides are for example sold by the company TAYCAunder the trade names "MICROTITANIUM DIOXIDE MT 500 B" or "MICROTITANIUMDIOXIDE MT 600 B", by the company DEGUSSA under the name "P 25", by thecompany WACKHERR under the name "Transparent titanium oxide PW", by thecompany MIYOSHI KASEI under the name "UFTR" and by the company TOMENunder the name "ITS".

The uncoated zinc oxides are for example sold by the company SUMITOMOunder the name "ULTRA FINE ZINC OXIDE POWDER", by the company PRESPERSEunder the name "FINEX 25" or by the company IKEDA under the name"MZO-25".

The uncoated cerium oxide is sold under the name "COLLOIDAL CERIUMOXIDE" by the company RHONE POULENC.

The iron oxides are for example sold by the company HILTON DAVIS underthe names "PUROXY YELLOW HIGH TRANSPARENCY", "PURE OXY RED HIGHTRANSPARENCY" and "PUROXY BLACK HIGH TRANSPARENCY".

According to the invention, the coated or uncoated nanopigments oftitanium oxide are particularly preferred.

The fat-soluble hydrocarbon chain-containing screening polymers usedaccording to the invention may be:

a) polyethyleneimine, chitin or chitosan polymers with an optionallysubstituted polyethylenic structure on which are grafted ultravioletradiation-absorbing molecules via an ester, amide, ether, thioether,sulfonyl or acyl functional group,

b) polymers resulting from the homo- or copolymerization of ultravioletradiation-absorbing molecules ("screening monomers") carrying anunsaturated group chosen from the radicals: allyl, vinyl, acrylamide,methacrylamide, vinyloxycarbonylmethyl, acrylamidoalkyl and especiallyacrylamidomethyl, methacrylamidoalkyl, acrylamido(phenyl)alkyl,methacrylamido(phenyl)alkyl, acryloyloxy, acryloyloxy-alkyl andacryloyloxypolyoxyethylene, optionally with other unsaturated monomers.

By way of ultraviolet radiation-absorbing molecules, the followingcompounds may be mentioned:

benzylidenecamphor and its derivatives substituted on the benzenenucleus,

isophthalylidenecamphor and terephthalylidenecamphor, optionallysubstituted on the benzene nucleus,

cinnamic acid, optionally substituted by one or more lower alkoxy groupsand its esters,

salicylic acid and its esters,

benzoic acid and its esters,

p-aminobenzoic acid and its derivatives which are alkylated on the aminogroup and their esters,

optionally substituted hydroxybenzophenones,

optionally substituted dibenzoylmethane,

benzotriazole and 2-arylbenzotriazoles

2-arylbenzimidazoles,

2-arylbenzofurans,

2-arylbenzoxazoles,

2-arylindoles,

mono- or diphenylcyanoacrylates,

absorbers of coumarin structure.

By way of unsaturated monomers which are copolymerizable with the"screening monomers", there may be mentioned:

acrylic, methacrylic, itaconic and crotonic acids or their esters,acrylamide and its derivatives, methacrylamide and its derivatives,acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, isoprene,butadiene, ethylene, propylene, vinyl esters, vinyl ethers, vinylchlorides and fluorides, vinylidene chloride, N-vinylpyrrolidone,N-methacryloyl-D-glucosamine and monoesters and diesters of maleic andfumaric acids.

In the present invention, "fat-soluble polymer" is understood to mean apolymer which is insoluble in water at a concentration greater than 0.1%by weight, at room temperature, and which is soluble or dispersible in acosmetic oil such as isopropyl adipate at a concentration of at least 1%by weight, at room temperature.

By way of fat-soluble hydrocarbon chain-containing screening polymerswhich can be used according to the invention, there may be mentioned byway of examples:

1) the polymers containing units of formula (I): ##STR1## in which

Z denotes:

a) --CONHCH₂ X, A denoting a hydrogen atom and X denoting a UV-absorbingaromatic group, such as those described in French Patents Nos.2,597,336; 2,237,912;

2,359,857 and 2,596,400, in which X is preferably chosen frombenzylidenecamphor radicals optionally substituted in positions 3 and 4by a C₁ -C₁₂ alkoxy radical or by a methylenedioxy radical, from2-(2'-hydroxyphenyl)benzotriazole radicals optionally substituted inposition 5' by a methyl or tert-octyl radical, from4-methoxy-4'-tert-butyldibenzoylmethane radical, 4-hydroxybenzophenoneradical, 2-hydroxybenzophenone radical optionally substituted by amethoxy group in position 4, from radicals derived from4-hydroxycoumarin and 7-hydroxycoumarin; ##STR2## where n is 0 or 1 whenn=0, A represents a hydrogen atom;

when n=1, A represents a hydrogen atom or a methyl radical,

R₁, R₂, R₃, R₄ and R₅, which are identical or different,

represent a hydrogen atom, a linear or branched alkyl radical having 1to 8 carbon atoms, an alkoxy radical having 1 to 4 carbon atoms, adialkylamino radical or a dialkylaminoalkyl radical of formula ##STR3##in which m is 1 to 3 and R₆ represents a methyl or ethyl radical, thesaid radicals being optionally quaternized by means of a quaternizingagent chosen from the group consisting of methyl chloride, dodecylbromide, dimethyl sulfate and chloroacetic acid;

Y being zero or being capable of denoting --CH₂ --, --CH(CH₃)--,##STR4## --C(CH₃)₂ --CH₂ --, these polymers being described in FrenchPatent No. 2,617,399;

2) the polymers derived from vinyl acetate containing the unit offormula (II) ##STR5## in which F represents a UV-absorbing radical suchas those described in French Patents Nos. 2,197,023 and 2,359,856;

the group ##STR6## being preferably chosen from a (C₁ -C₄p-dialkyl)aminobenzoate group, a cinnamate group which is optionallysubstituted by a methoxy, a salicylate group, a diphenylcyanoacrylategroup and a flufenate or 3'-trifluoromethyldiphenylamine-2-carboxylategroup;

3) the copolymers of polyethyleneimine with a molecular weight ofbetween 500 and 100,000 and (C₁ -C₄ para-dialkyl)aminobenzoic acidchloride, such as those described in U.S. Pat. No. 3,864,473;

4) the copolymers of monomers with ethylenic unsaturations and4-(N,N-diallylamino)benzoic acid derivatives or its esters, such asthose described in U.S. Pat. No. 3,795,733;

5) the polymerization products of the monomers of formula ##STR7## inwhich R denotes --(X)_(n) --O or .paren open-st.CH₂ CH₂ --O.parenclose-st._(n),

X denoting a divalent alkylene, arylene or alkylarylene radical,

n=1 to 1000,

R' denotes OH, N(R₁)₂,

R₁ denotes H, alkyl, aryl or alkylaryl,

the alkyl radicals having 1 to 20 carbon atoms, such as those describedfor example in Patent WO 88/09783;

6) the polymers derived from chitin and chitosan carrying at least oneUV-absorbing group of formula: ##STR8## in which: X and Y, independentlyof each other, denote hydrogen, a benzoyl radical of formula (IV) or acinnamoyl radical of formula (V) and Y may also denote acetyl: ##STR9##in which formulae: R¹, R² and R³, which are identical or different,denote hydrogen, C₁ -C₄ alkoxy, hydroxy or ##STR10## R⁴ denotinghydrogen, C₁ -C₄ alkyl, C₂ -C₄ monohydroxyalkyl or C₂ -C₄ dihydroxyalkyl, provided that at least one of the groups R¹, R² or R³ does notdenote hydrogen and that at most one of the groups R¹, R² or R³ denotes##STR11## R⁵ denotes C₁ -C₄ alkoxy p=3-20,000,

provided that when X denotes hydrogen, Y denotes neither hydrogen noracetyl;

such polymers are described in German Patent Application No. 3,912,122.

The preferred hydrocarbon chain-containing fat-soluble screeningpolymers according to the invention are polyacrylamides with optionallysubstituted benzylidenecamphor graft units X as defined above in 1)a).

The siloxane chain-containing screening polymers used according to theinvention are diorganopolysiloxanes containing in their molecule atleast one unit of formula: ##STR12## in which R' denotes a saturated orunsaturated C₁ -C₃₀ hydrocarbon group, a halogenated C₁ -C₈ hydrocarbongroup or a trimethylsilyloxy group;

a=1 or 2;

X=--A--Y

where A represents a divalent aliphatic or aromatic hydrocarbon radicalcontaining at least 2 carbon atoms and optionally containing one or moreoxygen atoms;

Y represents the residue of an ultraviolet radiation-screening molecule.

In addition to the units of formula (VI), the diorganopolysiloxane maycontain units of formulae: ##STR13## in which R' and a have the samemeaning as in formula (VI);

b is an integer denoting 1, 2 or 3;

Z=--O--Y, Y having the same meaning as in formula (VI).

By way of hydrocarbon group, there may be mentioned a C₁ -C₃₀ alkylradical, a C₂ -C₃₀ alkenyl radical, a cycloalkyl or aromatic radicalsuch as a phenyl or tolyl radical.

By way of halogenated hydrocarbon group, there may be mentioned a3,3,3-trifluoropropyl radical.

In the diorganopolysiloxane consisting of (VI), and optionally (VII) and(VIII), units, at least 40% in numerical terms of the R' radicals aremethyl radicals. The total number of (VI), (VII) and (VIII) units ispreferably less than or equal to 250 and is in particular between 2 and50.

Y preferably represents:

a benzylidenecamphor residue which is optionally substituted on thebenzene nucleus by hydroxyl, alkyl or C₁ -C₆ alkoxy radicals;

a C₁ -C₈ dialkyl benzalmalonate residue which is optionally substitutedon the benzene nucleus by hydroxy, alkyl or C₁ -C₆ alkoxy radicals;

a 2-(2'-hydroxyphenyl)benzotriazole residue optionally carrying on oneof the aromatic nuclei C₁ -C₈ alkyl or C₂ -C₈ alkenyl, halogen, alkoxy,carboxy, hydroxy, amino or tetraalkylpiperidyl substituents;

a dibenzoylmethane residue optionally carrying C₁ -C₈ alkyl or alkoxy orhydroxy substituents;

a benzophenone residue optionally carrying C₁ -C₈ alkyl or alkoxy orhydroxy substituents;

a benzoate residue substituted by hydroxy, C₁ -C₆ alkoxy, amino or mono-or di-(C₁ -C₆ alkyl)amino radicals.

Such siloxane chain-containing screening polymers are described inEuropean Patent Applications Nos. 0,335,777; 0,392,882; 0,388,218;0,392,883; 0,383,655 and 0,389,337 and in French Patents 2,550,787 and2,657,351 and in American patents U.S. Pat. Nos. 4,696,969; 4,554,369;4,562,278; 3,513,184 and 4,859,759.

The screening silicones preferred for use according to the invention arethose in which the radical Y denotes a benzylidenecamphor radical or anoptionally substituted 2-(2'-hydroxyphenyl)benzotriazole radical asdefined above.

The concentration of nanopigments in the compositions according to theinvention is between 0.1 and 15% by weight and preferably between 0.5and 10% by weight relative to the total weight of the composition.

The screening polymer(s) are present at a total concentration of between0.1 and 15% by weight and preferably between 0.5 and 10% by weightrelative to the total weight of the composition.

The nanopigment(s)/screening polymer(s) ratio by weight isadvantageously between 0.1 and 10 and preferably between 0.5 and 5.

The cosmetic composition of the invention may be used as composition forprotecting the human epidermis or the hair against ultraviolet rays, asan anti-sun composition or as a make-up product.

This composition may be provided in particular in the form of a lotion,a thickened lotion, a gel, an oil, a vesicular dispersion, a cream, amilk, a powder or a solid stick and may optionally be packaged as anaerosol and provided in the form of a foam or a spray.

It may contain the cosmetic adjuvants generally used, such as fattysubstances, organic solvents, silicones, thickeners, emollients, UV-A,UV-B or broad band sunscreen agents, antifoaming agents, moisturizingagents, perfumes, preservatives, surfactants, fillers, sequestrants,anionic, cationic, nonionic and amphoteric polymers or mixtures thereof,propellants, alkalinizing or acidifying agents, colorants, pigments ofmetallic oxides with a particle size of between 100 nm and 20,000 nmsuch as iron oxides, or any other ingredient generally used in thecosmetic field.

The fatty substances may consist of an oil or a wax or a mixturethereof, fatty acids, fatty alcohols, vaseline, paraffin, lanolin,hydrogenated lanolin or acetylated lanolin.

The oils are chosen from animal, vegetable, mineral or synthetic oilsand especially hydrogenated palm oil, hydrogenated castor oil, vaselineoil, paraffin oil, Purcellin oil, silicone oils and isoparaffins.

The waxes are chosen from animal, fossile, vegetable, mineral orsynthetic waxes. There may be mentioned especially beeswaxes, Carnaubawax, Candelilla wax, sugar cane wax, Japan wax, ozokerites, Montan wax,microcrystalline waxes, paraffins, silicone waxes and resins.

When the cosmetic composition according to the invention is used forprotecting the human epidermis against UV rays, or as an anti-suncomposition, it may be provided in the form of a suspension or adispersion in solvents or fatty substances, or alternatively in the formof an emulsion such as a cream or a milk, in the form of an ointment, agel, a solid stick or an aerosol foam.

The emulsions may contain, in addition, anionic, nonionic, cationic oramphoteric surface-active agents.

It may also be provided in the form of a vesicular dispersion of ionicor nonionic amphiphilic lipids which is prepared according to knownprocesses. The lipids may for example be swollen in an aqueous solutionto form spherules dispersed in the aqueous medium as described in thepublication BANGHAM, STANDISH & WATKINS, J. Mol. Biol., 13, 238 (1965)or in Patents FR-2,315,991 and 2,416,008 by the Applicant.

When the cosmetic composition according to the invention is used forprotecting the hair, it may be provided in the form of a rinse-offshampoo, lotion, gel or composition to be applied before or aftershampooing, before or after dyeing or bleaching, before, during or afterpermenent waving or hair straightening, a hair styling or treatmentlotion or gel, a lotion or gel for blow drying or hair setting, a hairlacquer, a composition for permanent waving or hair straightening, andfor dyeing or bleaching the hair.

When the composition is used as a make-up product for the eyelashes,eyebrows or the skin, such as a cream for treating the epidermis, afoundation, a lipstick, an eyeshadow, a blusher, a mascara or an eyeliner, it may be provided in solid or pasty, anhydrous or aqueous form,such as oil-in-water or water-in-oil emulsions, vesicular dispersions oralternatively suspensions.

The subject of the invention is also a process for protecting the humanepidermis and the hair against ultraviolet radiation, consisting inapplying to the skin or the hair an effective quantity of the abovecosmetic composition.

The invention will be illustrated more clearly by the nonlimitingexamples below.

EXAMPLE 1

An anti-sun cream of the following composition is prepared:

Titanium oxide coated with iron oxide and iron stearate (mean diameter15 nm) sold under the name "MICROTITANIUM DIOXIDE MT 100 F" by thecompany TAYCA 5 g

Polydimethylsiloxane containing a2-(3'-trimethylene-5'-methyl-2'-hydroxyphenyl)benzotriazole graft unitof formula: 5 g ##STR14## according to Example 1 of Application EP0,388,218

    ______________________________________    Mixture of glycerol stearate and poly-                            1       g    ethylene glycol stearate containing    100 moles of ethylene oxide sold    under the name "Arlacel 165" by    the company ICI    Isostearic acid         2       g    2-Octyldodecanol        15      g    Stearyl alcohol         1       g    Glycerin                3       g    Sorbitol in aqueous solution at 70% AI                            1.4     g AI    Cross-linked polyacrylic acid sold                            0.3     g    under the name "CARBOPOL 940" by    the company GOODRICH    Triethanolamine         0.4     g    Preservatives, antioxidant                            qs    Perfume                 qs    Water                   qs 100  g    ______________________________________

EXAMPLE 2

An anti-sun cream of the following composition is prepared:

    ______________________________________    Titanium oxide coated with iron oxide and                               5      g    iron stearate (mean diameter 15 nm) sold    under the name "MICROTITANIUM DIOXIDE MT    100 F" by the company TAYCA    Poly(4'-acrylamidomethyl-3-benzyli-                               5      g    denecamphor) of Example 1 of French    Patent No. 2,597,336 consisting of the    units:     ##STR15##    Mixture of glycerol stearate and poly-                               1      g    ethylene glycol stearate containing    100 moles of ethylene oxide sold under    the name "ARLACEL 165" by the company    ICI    Isostearic acid            2      g    2-Octyldodecanol           15     g    Stearyl alcohol            1      g    Glycerin                   3      g    Sorbitol in aqueous solution at 70% AI                               1.4    g AI    Cross-linked polyacrylic acid sold                               0.3    g    under the name "CARBOPOL 940" by    the company GOODRICH    Triethanolamine            0.4    g    Preservatives, antioxidant qs    Perfume qs    Water qs                   100    g    ______________________________________

EXAMPLE 3

An anti-sun O/W emulsion of the following composition is prepared:

    __________________________________________________________________________    Mixture of glycerol stearate and poly-   2  g    ethylene glycol stearate containing    100 moles of ethylene oxide sold under    the name "ARLACEL 165" by the company    ICI    Vaseline oil                             8  g    Stearic acid                             2  g    Lanolin                                  2  g    Stearyl alcohol                          1  g    Polydimethylsiloxane containing          2  g    2-(3'-trimethylene-2'-hydroxy-5'-    methylphenyl)-benzotriazole graft units    according to Application EP 0,392,883     ##STR16##    Glycerin                                 3  g    Sorbitol in aqueous solution at 70% AI   1.4                                                g AI    Hydroxyethyl cellulose modified by a     0.5                                                g    cetyl chain sold under the name    "NATROSOL PLUS GRADE 336 CS" by the    company AQUALON    Potassium hexadecylphosphate             0.5                                                g    Sodium acetate monohydrate               0.2                                                g    Colloidal cerium oxide sold in           2  g AI    aqueous solution at 20% AI by the    company RHONE POULENC under the name    "COLLOIDAL CERIUM OXIDE"    Preservatives qs    Water qs                                 100                                                g    __________________________________________________________________________

EXAMPLE 4

An anti-sun O/W emulsion of the following composition is prepared:

    __________________________________________________________________________    Mixture of glycerol stearate and poly-                                  2  g    ethylene glycol stearate containing    100 moles of ethylene oxide sold under    the name "ARLACEL 165" by the company    ICI    Vaseline oil                  8  g    Stearic acid                  2  g    Lanolin                       2  g    Stearyl alcohol               1  g    Mixture of polydimethylsiloxanes con-    taining 4'-trimethyleneoxy-3-benzyli-    denecamphor and 4'-oxy-3-benzylidene-    camphor graft units, which is prepared    according to Application EP 0,335,777,    and having the formula:     ##STR17##                    2  g    consisting of about:    55% polydimethylsiloxane. in which x = 0 to 20, y = 1    to 4, z = 0    5% polydimethylsiloxane in which x = 0 to 21,    y = 0, z = 1 to 4    40% polydimethylsiloxane in which x = 0 to 16, y = 1    to 3, z = 1 to 3,    BC denoting the 3-benzylidenecamphor radical    Glycerin                      3  g    Sorbitol in aqueous solution at 70% AI                                  1.4                                     g AI    Hydroxyethyl cellulose modified by a                                  0.5                                     g    cetyl chain sold under the name    "NATROSOL PLUS GRADE 330 CS" by the    company AQUALON    Potassium hexadecylphosphate  0.5                                     g    Sodium acetate monohydrate    0.2                                     g    Titanium oxide coated with iron oxide                                  2.5                                     g    and iron stearate (mean diameter 15 nm)    sold under the name "MICROTITANIUM    DIOXIDE MT 100 F" by the company TAYCA    Preservatives qs    Water qs                      100                                     g    __________________________________________________________________________

EXAMPLE 5

An anti-sun O/W emulsion of the following composition is prepared:

    __________________________________________________________________________    Mixture of glycerol stearate and poly-                                  2  g    ethylene glycol stearate containing    100 moles of ethylene oxide sold under    the name "ARLACEL 165" by the company    ICI    Vaseline oil                  8  g    Stearic acid                  2  g    Lanolin                       2  g    Stearyl alcohol               1  g    Graft polydimethylsiloxane derived                                  2  g    from benzophenone of formula:     ##STR18##    Glycerin                      3  g    Sorbitol in aqueous solution at 70% AI                                  1.4                                     g AI    Hydroxyethyl cellulose modified by a                                  0.5                                     g    cetyl chain sold under the name    "NATROSOL PLUS GRADE 330 CS" by the    company AQUALON    Potassium hexadecylphosphate  0.5                                     g    Sodium acetate monohydrate    0.2                                     g    Zinc oxide sold under the name "ULTRA                                  2  g    FINE ZINC OXIDE POWDER" by the company    SUMITOMO    Preservatives qs    Water qs                      100                                     g    __________________________________________________________________________

EXAMPLE 6

A cream gel of the following composition is prepared:

    __________________________________________________________________________    Glycerin                               3 g    Vaseline oil                           5 g    Oil-in-water emulsion of cross-linked                                          1.2 g AI    acrylamide/sodium 2-acrylamido-2-    in copolymer    methylpropanesulfonate copolymer,    sold by the company SEPPIC under the    name "SEPIGEL 305" with 40% AI in    copolymer    Titanium oxide coated with iron oxide                                         1.33 g    and iron stearate (mean diameter 15 nm)    sold under the name "MICROTITANIUM    DIOXIDE MT 100 F" by the company TAYCA    Graft polydimethylsiloxane derived   2.67 g    from benzophenone of formula:     ##STR19##    according to French Patent Application.    FR 2,657,351    Mixture of dimethiconol (13%), octa-  5 g    methylcyclotetrasiloxane and decamethyl-    cyclopentasiloxane (87%), sold under the    name "Q2-1401" by the company DOW    CORNING    Methyl polymethacrylate powder (15μ)                                          3 g    sold under the name "MICROPEARL M 100"    by the company SEPPIC    Preservatives qs    Water qs                             100 g    __________________________________________________________________________

We claim:
 1. A screening cosmetic composition, comprising, in acosmetically acceptable carrier, at least one coated nanopigment ofmetallic oxides selected from the group consisting of titanium, zinc,cerium, zirconium and iron oxides and mixtures thereof, with a meandiameter of less than 100 nm, having undergone one or more surfacetreatments of a chemical, electronic, mechanicochemical or mechanicalnature with compounds selected from the group consisting of amino acids,beeswax, fatty acids, fatty alcohols, anionic surfactants, lecithins,sodium, potassium, zinc, iron and aluminum salts of fatty acids,metallic alkoxides, polyethylene, silicones, proteins, alkanolamines,silicon oxides, metallic oxides and sodium hexametaphosphate, and atleast one polymer with a siloxane structure carrying at least oneultraviolet-absorbing group, said polymer with the siloxane structureconsisting of diorganopolysiloxane containing in their molecule at leastone unit of formula: ##STR20## in which: R' denotes a saturated orunsaturated C₁ -C₃₀ hydrocarbon group, a halogenated C₁ -C₈ hydrocarbongroup or a trimethylsilyloxy group;a=1 or 2; X=--A--Ywhere A representsa divalent aliphatic or aromatic hydrocarbon radical containing at least2 carbon atoms and optionally containing one or more oxygen atoms, and Yrepresents the residue of an ultraviolet radiation-screening moleculewhich is a benzylidenecamphor residue which is unsubstituted orsubstituted on the benzene nucleus by a hydroxyl, C₁ -C₆ alkyl or alkoxyradical; a C₁ -C₈ dialkyl benzalmalonate residue which is unsubstitutedor substituted on the benzene nucleus by hydroxyl, C₁ -C₆ alkyl oralkoxy radicals; a 2-(2'-hydroxyphenyl)benzotriazole residue which isunsubstituted or carrying on one of the aromatic nuclei C₁ -C₈ alkyl, C₂-C₈ alkenyl, halogen, alkoxy, carboxy, hydroxy or amino substituents; adibenzoylmethane residue which is unsubstituted or carrying C₁ -C₈ alkylor alkoxy or hydroxy substituents; or a benzoate residue which issubstituted by hydroxy, C₁ -C₈ alkoxy, amino or mono- or di(C₁ -C₆alkyl)amino radicals.
 2. Cosmetic composition according to claim 1,wherein the nanopigments of metallic oxides have a diameter of between 5and 50 nm.
 3. Cosmetic composition according to claim 1, wherein themetallic oxide is titanium oxide.
 4. Cosmetic composition according toclaim 1, wherein the coated nanopigment of metallic oxides is a pigmentof titanium oxide coated with silica, with silica and alumina, withsilica and iron oxide, with alumina and silicone, with alumina, withalumina and aluminum stearate, with alumina and aluminum laurate, withiron oxide and iron stearate, with zinc oxide and zinc stearate, withsilica and alumina and silicone, with silica and alumina and aluminumstearate and silicone, with triethanolamine, with stearic acid or withsodium hexametaphosphate.
 5. Cosmetic composition according to claim 1,which contains 0.1 to 15% by weight relative to the total weight of thecomposition, of at least one nanopigment of metallic oxides.
 6. Cosmeticcomposition according to claim 1, wherein the diorganopolysiloxanecontains, in addition, units having the formulae: ##STR21## in which R'and a have the meanings indicated in claim 1, b is an integer equal to1, 2 or 3, Z=--O--Y, Y having the same meaning as in claim 1, at least40% in numerical terms of the R' radicals denoting methyl.
 7. Cosmeticcomposition according to claim 1, which comprises a polydimethylsiloxanewith 2-(3'-trimethylene-5'-methyl-2'-hydroxyphenyl)benzotriazole graftunit(s).
 8. Cosmetic composition according to claim 1, which comprises amixture of polydimethylsiloxanes with4'-trimethyleneoxy-3-benzylidenecamphor and 4'-oxy-3-benzylidenecamphorgraft units.
 9. Cosmetic composition according to claim 1, whichcontains 0.1 to 15% by weight, relative to the total weight of thecomposition, of at least one fat-soluble screening polymer withhydrocarbon or siloxane structure.
 10. Cosmetic composition according toclaim 1, wherein the nanopigment(s)/screening polymer(s) ratio by weightis between 0.1 and
 10. 11. Cosmetic composition according to claim 1,which constitutes a composition for protecting the human epidermis or ananti-sun composition and is provided in the form of a lotion, athickened lotion, a gel, an oil, a vesicular dispersion, a cream, amilk, a powder, a solid stick, a foam or a spray.
 12. Cosmeticcomposition according to claim 1, which constitutes a make-upcomposition for the eyelashes, eyebrows or skin and is in solid orpasty, anhydrous or aqueous form, as emulsion, suspension or vesiculardispersion.
 13. Cosmetic compositin according to claim 1, which is usedfor protecting the hair against ultraviolet rays, which is in the formof a rinse-off shampoo, lotion, gel or composition to be applied beforeor after shampooing, before or after dyeing or bleaching, before, duringor after permenent waving or hair straightening, a hair styling ortreatment lotion or gel, a lotion or gel for blow drying or hairsetting, a hair lacquer, a composition for permanent waving or hairstraightening, and for dyeing or bleaching the hair.
 14. Cosmeticcomposition according to claim 1, which comprises, in addition, cosmeticadjuvants selected from the group consisting of fatty substances,organic solvents, silicones, thickeners, emollients, UV-A, UV-B andbroad band sunscreen agents, antifoaming agents, moisturizing agents,perfumes, preservatives, surfactants, fillers, sequestrants, anionic,cationic, nonionic and amphoteric polymers and mixtures thereof,propellants, alkalinizing and acidifying agents, colorants, and pigmentsof metallic oxides with a particle size of between 100 nm and 20,000 nm.15. Process for protecting the human epidermis and the hair againstultraviolet radiation of wavelengths of between 280 and 400 nm,consisting in applying to the skin or the hair an effective quantity ofa cosmetic composition according to any one of claims 1 to 14.